Add support for HandleBlockingMessage to NaClMessageScanner

ppapi/proxy/nacl_message_scanner.cc

Index: ppapi/proxy/nacl_message_scanner.cc
diff --git a/ppapi/proxy/nacl_message_scanner.cc b/ppapi/proxy/nacl_message_scanner.cc
index 769a03f2885ceb2cfbde6694c86506e09ce529a4..311d6082f5109af0de463f2b95d314b38ff7fb41 100644
--- a/ppapi/proxy/nacl_message_scanner.cc
+++ b/ppapi/proxy/nacl_message_scanner.cc
@@ -187,6 +187,15 @@ class MessageScannerImpl {
     return true;
   }
 
+  bool ScanSyncMessage(ScanningResults* results) {
+    typename base::TupleTypes<
+        typename MessageType::Schema::SendParam>::ValueTuple params;
+    if (!MessageType::ReadSendParam(msg_, &params))
+      return false;
+    ScanTuple(params, results);

[Mark Seaborn, 2015/12/17 01:46:54]

This needs to be:

  bool ScanSyncMessage(ScanningResults* results) {
    typename base::TupleTypes<typename MessageType::Schema::SendParam>
        ::ValueTuple params;
    if (!MessageType::ReadSendParam(msg_, &params))
      return false;
    // If we need to rewrite the message, write the message id first.
    if (results->new_msg) {
      results->new_msg->set_sync();
      int id = IPC::SyncMessage::GetMessageId(*msg_);
      results->new_msg->WriteInt(id);
    }
    ScanTuple(params, results);
    return true;
  }

I figured this out for my change, https://codereview.chromium.org/1512733003/.

I was able to test that on Linux by setting "rewrite_msg = true" below.

[dmichael (off chromium), 2015/12/17 19:04:29]

Done.

+    return true;
+  }
+
   bool ScanReply(ScanningResults* results) {
     typename base::TupleTypes<typename MessageType::Schema::ReplyParam>
         ::ValueTuple params;
@@ -221,6 +230,16 @@ class MessageScannerImpl {
           return false; \
         break; \
       }
+#define CASE_FOR_SYNC_MESSAGE(MESSAGE_TYPE) \
+  case MESSAGE_TYPE::ID: { \

[Mark Seaborn, 2015/12/17 01:46:54]

Nit: can you make the indentation alignment match the macros above and below?

[dmichael (off chromium), 2015/12/17 19:04:29]

Done (actually changed the others; not sure why I had them weirdly indented. I
think this is now proper style.)

+    MessageScannerImpl<MESSAGE_TYPE> scanner(&msg); \
+    if (rewrite_msg) \
+      results.new_msg.reset(new IPC::Message(msg.routing_id(), msg.type(), \
+                                             IPC::Message::PRIORITY_NORMAL)); \
+    if (!scanner.ScanSyncMessage(&results)) \
+      return false; \
+    break; \
+  }
 #define CASE_FOR_REPLY(MESSAGE_TYPE) \
       case MESSAGE_TYPE::ID: { \
         MessageScannerImpl<MESSAGE_TYPE> scanner(&msg); \
@@ -326,6 +345,7 @@ bool NaClMessageScanner::ScanMessage(
     CASE_FOR_MESSAGE(PpapiMsg_PPBAudio_NotifyAudioStreamCreated)
     CASE_FOR_MESSAGE(PpapiMsg_PPPMessaging_HandleMessage)
     CASE_FOR_MESSAGE(PpapiPluginMsg_ResourceReply)
+    CASE_FOR_SYNC_MESSAGE(PpapiMsg_PPPMessageHandler_HandleBlockingMessage)
     CASE_FOR_REPLY(PpapiHostMsg_OpenResource)
     CASE_FOR_REPLY(PpapiHostMsg_PPBGraphics3D_Create)
     CASE_FOR_REPLY(PpapiHostMsg_PPBGraphics3D_CreateTransferBuffer)